Denise Cysneiros - Academia.edu (original) (raw)
Papers by Denise Cysneiros
Journal of Hazardous Materials, Aug 1, 2021
Recent trends in food waste and its management have increasingly started to focus on treating it ... more Recent trends in food waste and its management have increasingly started to focus on treating it as a reusable resource. The hazardous impact of food waste such as the release of greenhouse gases, deterioration of water quality and contamination of land areas are a major threat posed by food waste. Under the circular economy principles, food waste can be used as a sustainable supply of high-value energy, fuel, and nutrients through green techniques such as anaerobic digestion, co-digestion, composting, enzymatic treatment, ultrasonic, hydrothermal carbonization. Recent advances made in anaerobic co-digestion are helping in tackling dual or even multiple waste streams at once with better product yields. Integrated approaches that employ pre-processing the food waste to remove obstacles such as volatile fractions, oils and other inhibitory components from the feedstock to enhance their bioconversion to reduce sugars. Research efforts are also progressing in optimizing the operational parameters such as temperature, pressure, pH and residence time to enhance further the output of products such as methane, hydrogen and other platform chemicals such as lactic acid, succinic acid and formic acid. This review brings together some of the recent progress made in the green strategies towards food waste valorization.
Copyright © 2013 Katarzyna Bialek et al. This is an open access article distributed under the Cre... more Copyright © 2013 Katarzyna Bialek et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The feasibility of anaerobic digestion of dairy wastewater at 10∘C was investigated in a high height: diameter ratio EGSB reactor. Stable performance was observed at an applied organic loading rate (OLR) of 0.5–2 kgCODm−3 d−1 with chemical oxygen demand (COD) removal efficiencies above 85%. When applied OLR increased to values above 2 kgCODm−3 d−1, biotreatment efficiency deteriorated, with methanogenesis being the rate-limiting step.The bioreactor recovered quickly (3 days) after reduction of the OLR. qPCR results showed a reduction in the abundance of hydrogenotrophic methanogenic Methanomicrobiales and Methanobacteriales throughout the steady state period followed by a sharp increase in their numbers (111-fold) after the load sh...
The potential for using the crop maize (Zea mays) for the production of biogas in simple anaerobi... more The potential for using the crop maize (Zea mays) for the production of biogas in simple anaerobic leach beds was evaluated. The results showed that leach beds coupled to high-rate methanogenic reactors performed better than other systems on a specific methane yield per gram of substrate added basis while their performance on a volumetric gas yield basis was poorer. Initial experiments using a single stage digester showed rapid acidification due to the low buffering capacity of the system. To overcome this problem, leach beds were used as part of a two-phase system in which the intermediate metabolic products were flushed out and used as substrate for a second stage methanogenic reactor. Further experiments simulated the effect of a hydraulic flush in the leach bed using clean water as the flush liquid. Methane potential of the leachate was estimated based on the cumulative soluble chemical oxygen demand (SCOD) production. Under this operation mode, the effect of substrate to inocul...
FEMS Microbiology Ecology, 2018
This paper explores low-temperature anaerobic digestion of a synthetic sewage-based wastewater wi... more This paper explores low-temperature anaerobic digestion of a synthetic sewage-based wastewater with a focus on microbial community adaptation when using a mesophilic starting community.
Long-term (732 days) anaerobic treatment of synthetic domestic sewage was studied in a hybrid EGS... more Long-term (732 days) anaerobic treatment of synthetic domestic sewage was studied in a hybrid EGSB reactor, which contained a fixed-film filter section, in addition to a granular sludge bed. The reactor was operated at 12˚C and optimum operating conditions were observed at a hydraulic retention time of 18 hours and an organic loading rate of 0.625 kg COD m-3 d-1 , when chemical oxygen demand (COD) removal, based on total, suspended, colloidal and soluble fractions , reached 80%, 71%, 45% and 85%, respectively. Carbohydrate and protein removal rates routinely reached 100%. Scanning electron microscopy and energy dispersive X-ray microscopy analysis revealed that the significant phosphate (P) removal recorded during the trial (up to 78%) was as a result of P accumulation by the biomass fraction of the fixed-film section. Specific methanogenic activity profiles of the biomass with propionate as substrate increased by 90% at 12°C during the trial, suggesting a degradation pathway via propionate. A 6-fold increase of the protein hydrolysis rate at 12°C during the trial demonstrated the successful development of an active proteolytic community over time. Denaturing gradient gel electrophoresis analysis of the bacterial and archaeal 16S rRNA gene sequences (based on both extracted DNA and RNA) highlighted community changes over time, and specifically within the active fraction of the community.
Water Science & Technology, 2012
In this study, the ability of various sludges to digest a diverse range of cellulose and cellulos... more In this study, the ability of various sludges to digest a diverse range of cellulose and cellulose-derived substrates was assessed at different temperatures to elucidate the factors affecting hydrolysis. For this purpose, the biogas production was monitored and the specific biogas activity (SBA) of the sludges was employed to compare the performance of three anaerobic sludges on the degradation of a variety of complex cellulose sources, across a range of temperatures. The sludge with the highest performance on complex substrates was derived from a full-scale bioreactor treating sewage at 37 °C. Hydrolysis was the rate-limiting step during the degradation of complex substrates. No activity was recorded for the synthetic cellulose compound carboxymethylcellulose (CMC) using any of the sludges tested. Increased temperature led to an increase in hydrolysis rates and thus SBA values. The non-granular nature of the mesophilic sludge played a positive role in the hydrolysis of solid substr...
Biotechnology and Bioengineering, 2004
The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions wa... more The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions was studied in three parallel lab-scale UASB-reactors and in cobalt-limited enriched cultures. Reactors R1, R2, and R3 were fed with methanol in a bicarbonate-buffered medium, supplied with iron and macronutrients: in R1 all metals were supplied (control), R2 was cobalt deprived, and in R3 all metals were deprived. In the 136 days of continuous experiment, a drop in performance was observed over the last 30 days. Particularly in R3, both methanol removal and methane formation dropped by 7.1% and 13.7%, respectively, compared to the control reactor, R1. When the medium was cobalt-deprived, acetate was not produced and, as a consequence, the enriched consortium lost its capacity to degrade acetate, indicating that the acetotrophic microorganisms were washed out. The addition of 0.5 AM of cobalt to a cobalt-deprived enrichment culture led to acetate accumulation. The results obtained in this study indicate that the mixed consortium requires a proper amount of cobalt, and its addition to a concentration of 0.1 AM leads to the highest methanol conversion rate, with methane as the sole end product from methanol.
Bioresource Technology, 2011
Production of electricity from samples obtained during anaerobic digestion of grass silage was ex... more Production of electricity from samples obtained during anaerobic digestion of grass silage was examined using single-chamber air-cathode mediator-less microbial fuel cells (MFCs). The samples were obtained from anaerobic reactors at start-up conditions after 3 and 10 days of operation under psychrophilic (15°C) and mesophilic (37°C) temperatures. Electricity was directly produced from all samples at a concentration of 1500 mg COD L À1. Power density obtained from the samples, as a sole carbon source, ranged from 56 ± 3 W m À3 to 31 ± 1 W m À3 for the mesophilic and psychrophilic samples, respectively. Coulombic efficiencies ranged from 18 ± 1% to 12 ± 1% for the same samples. The relationship between the maximum voltage output and initial COD concentration appeared to follow saturation kinetics at the external resistance of 217 X. Chemical oxygen demand (COD) removal was over 90% and total phenolics removal was in the range of 30-75% for all samples tested, with a standard amount of 60 mg L À1 total phenolics removed for every sample. Our results indicate that generating electricity from solution samples of anaerobic reactors utilizing grass silage is possible, opening the possibility for combination of anaerobic digestion with MFC technology for energy generation.
Bioresource Technology, 2012
Applied Microbiology and Biotechnology, 2013
Water Science & Technology, 2011
Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasi... more Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasibility of psychrophilic (low temperature) digestion of perennial rye grass in a long term experiment (150 days) for the first time. The reactors were operated in parallel at 3 different temperatures, 10, 15 and 37 °C. Hydrolysis, acidification and methanogenesis were assessed by VS degradation, by soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFA) production, and by methane production, respectively. Hydrolysis was the rate-limiting step at all temperatures and the rates and extent of hydrolysis were considerably lower at 15 and 10 °C, than at 37 °C. The total VS degradation was 53%, 34% and 19% at 37, 15 and 10 °C, respectively. Acidification was not affected by temperature and VFA production and consumption was balanced in all cases, except at 10 °C. Methane yields were 0.215 m3 CH4 kg−1 VS−1 added, 0.160 m3 CH4 kg−1 VS−1 added and 0.125 m3 CH4 kg−1 VS−1 added at 37, 1...
Engenheira Civil pela UFPE. Mestre em Hidraulica e Saneamento pela EESC/USP. Ph.D em Tecnologia A... more Engenheira Civil pela UFPE. Mestre em Hidraulica e Saneamento pela EESC/USP. Ph.D em Tecnologia Ambiental pela Universidade Agricola de Wageningen, Holanda. Profa. Adjunta do Depto. de Eng. Civil no Centro de Tecnologia e Geociencias, UFPE, Coord. e Profa. da Area de Tecnologia Ambiental e Recursos Hidricos do Mestrado e Doutorado em Engenharia Civil e do Mestrado em Gestao e Politicas Ambientais da UFPE.
Applied Sciences
Wheat straw (WS) is considered a favourable substrate for biogas production. However, due to its ... more Wheat straw (WS) is considered a favourable substrate for biogas production. However, due to its rigid structure and high carbon to nitrogen (C/N ratio), its biodegradability during anaerobic digestion (AD) is usually low. In the present study, the effect of steam explosion pre-treatment on WS, combined with C/N adjustment with inorganic nitrogen, on biogas production was evaluated. Additionally, co-digestion of WS with protein-rich agri-industrial by-products (dried distillers’ grains with solubles (DDGS) and rapeseed meal (RM)) was assessed. Steam explosion enhanced biogas production from WS, whereas the addition of NH4Cl was beneficial (p < 0.05) for the digestion of steam-exploded wheat straw (SE). Furthermore, mono-digestion of the four different substrates seemed to be efficient in both inoculum to substrate ratios (I/S) tested (3.5 and 1.75 (w/w)). Finally, during co-digestion of WS and SE with DDGS and RM, an increase in the cumulative methane production was noted when hi...
Journal of Hazardous Materials
Frontiers in Microbiology, 2016
We report, for the first time, extensive biologically mediated phosphate removal from wastewater ... more We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12 • C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (∼2%) within the sludge bed and fixed-film biofilms. 4 , 6-diamidino-2-phenylindole (DAPI) staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP) granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD) removal was recorded, throughout the 732day trial, at applied organic loading rates between 0.4 and 1.5 kg COD m −3 d −1 and hydraulic retention times of 8-24 h, while phosphate removal efficiency ranged from 28 to 78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12 • C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina MiSeq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterized polyphosphate accumulating organisms (PAOs) such as Rhodocyclus, Chromatiales, Actinobacter, and Acinetobacter was recorded at low numbers. However, it is unknown as yet if these were responsible for the luxury polyP uptake observed in this system. The possibility of efficient phosphate removal and recovery from wastewater during AD would represent a major advance in the scope for widespread application of anaerobic wastewater treatment technologies.
RESUMO O metanol é um importante composto orgânico presente em diversos tipos de águas residuária... more RESUMO O metanol é um importante composto orgânico presente em diversos tipos de águas residuárias, como em indústrias de polpa e papel, amido de batata e unidade s de gaseificação de carvão. Algumas águas residuárias contendo metanol são descarregadas com altas temperaturas, tornando atrativa a aplicação do tratamento termofílico. Em ambiente anaeróbio, o metanol pode ser consumido por acetogênicas e metanogênicas. Em condições mesofílicas, a concentração do substrato, o pH do reator, a concentração de bicarbonato e a concentração de cobalto foram os fatores ambientais relevantes na conversão anaeróbia do metanol. Entretanto, pouco se conhece sobre a degradação de
Applied microbiology and biotechnology, 2014
The application of low-temperature (10 °C) anaerobic digestion (LtAD) for the treatment of comple... more The application of low-temperature (10 °C) anaerobic digestion (LtAD) for the treatment of complex dairy-based wastewater in an inverted fluidised bed (IFB) reactor was investigated. Inadequate mixing intensity provoked poor hydrolysis of the substrate (mostly protein), which resulted in low chemical oxygen demand (COD) removal efficiency throughout the trial, averaging ~69 % at the best operational period. Overgrowth of the attached biomass to the support particles (Extendospheres) induced bed stratification by provoking agglutination of the particles and supporting their washout by sedimentation, which contributed to unstable bioprocess performance at the organic loading rates (OLRs) between 0.5 and 5 kg COD m(-3) day(-1). An applied OLR above 2 kg COD m(-3) day(-1) additionally promoted acidification and strongly influenced the microbial composition and dynamics. Hydrogenotrophic methanogens appeared to be the mostly affected group by the Extendospheres particle washout as a decr...
Journal of Hazardous Materials, Aug 1, 2021
Recent trends in food waste and its management have increasingly started to focus on treating it ... more Recent trends in food waste and its management have increasingly started to focus on treating it as a reusable resource. The hazardous impact of food waste such as the release of greenhouse gases, deterioration of water quality and contamination of land areas are a major threat posed by food waste. Under the circular economy principles, food waste can be used as a sustainable supply of high-value energy, fuel, and nutrients through green techniques such as anaerobic digestion, co-digestion, composting, enzymatic treatment, ultrasonic, hydrothermal carbonization. Recent advances made in anaerobic co-digestion are helping in tackling dual or even multiple waste streams at once with better product yields. Integrated approaches that employ pre-processing the food waste to remove obstacles such as volatile fractions, oils and other inhibitory components from the feedstock to enhance their bioconversion to reduce sugars. Research efforts are also progressing in optimizing the operational parameters such as temperature, pressure, pH and residence time to enhance further the output of products such as methane, hydrogen and other platform chemicals such as lactic acid, succinic acid and formic acid. This review brings together some of the recent progress made in the green strategies towards food waste valorization.
Copyright © 2013 Katarzyna Bialek et al. This is an open access article distributed under the Cre... more Copyright © 2013 Katarzyna Bialek et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The feasibility of anaerobic digestion of dairy wastewater at 10∘C was investigated in a high height: diameter ratio EGSB reactor. Stable performance was observed at an applied organic loading rate (OLR) of 0.5–2 kgCODm−3 d−1 with chemical oxygen demand (COD) removal efficiencies above 85%. When applied OLR increased to values above 2 kgCODm−3 d−1, biotreatment efficiency deteriorated, with methanogenesis being the rate-limiting step.The bioreactor recovered quickly (3 days) after reduction of the OLR. qPCR results showed a reduction in the abundance of hydrogenotrophic methanogenic Methanomicrobiales and Methanobacteriales throughout the steady state period followed by a sharp increase in their numbers (111-fold) after the load sh...
The potential for using the crop maize (Zea mays) for the production of biogas in simple anaerobi... more The potential for using the crop maize (Zea mays) for the production of biogas in simple anaerobic leach beds was evaluated. The results showed that leach beds coupled to high-rate methanogenic reactors performed better than other systems on a specific methane yield per gram of substrate added basis while their performance on a volumetric gas yield basis was poorer. Initial experiments using a single stage digester showed rapid acidification due to the low buffering capacity of the system. To overcome this problem, leach beds were used as part of a two-phase system in which the intermediate metabolic products were flushed out and used as substrate for a second stage methanogenic reactor. Further experiments simulated the effect of a hydraulic flush in the leach bed using clean water as the flush liquid. Methane potential of the leachate was estimated based on the cumulative soluble chemical oxygen demand (SCOD) production. Under this operation mode, the effect of substrate to inocul...
FEMS Microbiology Ecology, 2018
This paper explores low-temperature anaerobic digestion of a synthetic sewage-based wastewater wi... more This paper explores low-temperature anaerobic digestion of a synthetic sewage-based wastewater with a focus on microbial community adaptation when using a mesophilic starting community.
Long-term (732 days) anaerobic treatment of synthetic domestic sewage was studied in a hybrid EGS... more Long-term (732 days) anaerobic treatment of synthetic domestic sewage was studied in a hybrid EGSB reactor, which contained a fixed-film filter section, in addition to a granular sludge bed. The reactor was operated at 12˚C and optimum operating conditions were observed at a hydraulic retention time of 18 hours and an organic loading rate of 0.625 kg COD m-3 d-1 , when chemical oxygen demand (COD) removal, based on total, suspended, colloidal and soluble fractions , reached 80%, 71%, 45% and 85%, respectively. Carbohydrate and protein removal rates routinely reached 100%. Scanning electron microscopy and energy dispersive X-ray microscopy analysis revealed that the significant phosphate (P) removal recorded during the trial (up to 78%) was as a result of P accumulation by the biomass fraction of the fixed-film section. Specific methanogenic activity profiles of the biomass with propionate as substrate increased by 90% at 12°C during the trial, suggesting a degradation pathway via propionate. A 6-fold increase of the protein hydrolysis rate at 12°C during the trial demonstrated the successful development of an active proteolytic community over time. Denaturing gradient gel electrophoresis analysis of the bacterial and archaeal 16S rRNA gene sequences (based on both extracted DNA and RNA) highlighted community changes over time, and specifically within the active fraction of the community.
Water Science & Technology, 2012
In this study, the ability of various sludges to digest a diverse range of cellulose and cellulos... more In this study, the ability of various sludges to digest a diverse range of cellulose and cellulose-derived substrates was assessed at different temperatures to elucidate the factors affecting hydrolysis. For this purpose, the biogas production was monitored and the specific biogas activity (SBA) of the sludges was employed to compare the performance of three anaerobic sludges on the degradation of a variety of complex cellulose sources, across a range of temperatures. The sludge with the highest performance on complex substrates was derived from a full-scale bioreactor treating sewage at 37 °C. Hydrolysis was the rate-limiting step during the degradation of complex substrates. No activity was recorded for the synthetic cellulose compound carboxymethylcellulose (CMC) using any of the sludges tested. Increased temperature led to an increase in hydrolysis rates and thus SBA values. The non-granular nature of the mesophilic sludge played a positive role in the hydrolysis of solid substr...
Biotechnology and Bioengineering, 2004
The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions wa... more The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions was studied in three parallel lab-scale UASB-reactors and in cobalt-limited enriched cultures. Reactors R1, R2, and R3 were fed with methanol in a bicarbonate-buffered medium, supplied with iron and macronutrients: in R1 all metals were supplied (control), R2 was cobalt deprived, and in R3 all metals were deprived. In the 136 days of continuous experiment, a drop in performance was observed over the last 30 days. Particularly in R3, both methanol removal and methane formation dropped by 7.1% and 13.7%, respectively, compared to the control reactor, R1. When the medium was cobalt-deprived, acetate was not produced and, as a consequence, the enriched consortium lost its capacity to degrade acetate, indicating that the acetotrophic microorganisms were washed out. The addition of 0.5 AM of cobalt to a cobalt-deprived enrichment culture led to acetate accumulation. The results obtained in this study indicate that the mixed consortium requires a proper amount of cobalt, and its addition to a concentration of 0.1 AM leads to the highest methanol conversion rate, with methane as the sole end product from methanol.
Bioresource Technology, 2011
Production of electricity from samples obtained during anaerobic digestion of grass silage was ex... more Production of electricity from samples obtained during anaerobic digestion of grass silage was examined using single-chamber air-cathode mediator-less microbial fuel cells (MFCs). The samples were obtained from anaerobic reactors at start-up conditions after 3 and 10 days of operation under psychrophilic (15°C) and mesophilic (37°C) temperatures. Electricity was directly produced from all samples at a concentration of 1500 mg COD L À1. Power density obtained from the samples, as a sole carbon source, ranged from 56 ± 3 W m À3 to 31 ± 1 W m À3 for the mesophilic and psychrophilic samples, respectively. Coulombic efficiencies ranged from 18 ± 1% to 12 ± 1% for the same samples. The relationship between the maximum voltage output and initial COD concentration appeared to follow saturation kinetics at the external resistance of 217 X. Chemical oxygen demand (COD) removal was over 90% and total phenolics removal was in the range of 30-75% for all samples tested, with a standard amount of 60 mg L À1 total phenolics removed for every sample. Our results indicate that generating electricity from solution samples of anaerobic reactors utilizing grass silage is possible, opening the possibility for combination of anaerobic digestion with MFC technology for energy generation.
Bioresource Technology, 2012
Applied Microbiology and Biotechnology, 2013
Water Science & Technology, 2011
Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasi... more Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasibility of psychrophilic (low temperature) digestion of perennial rye grass in a long term experiment (150 days) for the first time. The reactors were operated in parallel at 3 different temperatures, 10, 15 and 37 °C. Hydrolysis, acidification and methanogenesis were assessed by VS degradation, by soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFA) production, and by methane production, respectively. Hydrolysis was the rate-limiting step at all temperatures and the rates and extent of hydrolysis were considerably lower at 15 and 10 °C, than at 37 °C. The total VS degradation was 53%, 34% and 19% at 37, 15 and 10 °C, respectively. Acidification was not affected by temperature and VFA production and consumption was balanced in all cases, except at 10 °C. Methane yields were 0.215 m3 CH4 kg−1 VS−1 added, 0.160 m3 CH4 kg−1 VS−1 added and 0.125 m3 CH4 kg−1 VS−1 added at 37, 1...
Engenheira Civil pela UFPE. Mestre em Hidraulica e Saneamento pela EESC/USP. Ph.D em Tecnologia A... more Engenheira Civil pela UFPE. Mestre em Hidraulica e Saneamento pela EESC/USP. Ph.D em Tecnologia Ambiental pela Universidade Agricola de Wageningen, Holanda. Profa. Adjunta do Depto. de Eng. Civil no Centro de Tecnologia e Geociencias, UFPE, Coord. e Profa. da Area de Tecnologia Ambiental e Recursos Hidricos do Mestrado e Doutorado em Engenharia Civil e do Mestrado em Gestao e Politicas Ambientais da UFPE.
Applied Sciences
Wheat straw (WS) is considered a favourable substrate for biogas production. However, due to its ... more Wheat straw (WS) is considered a favourable substrate for biogas production. However, due to its rigid structure and high carbon to nitrogen (C/N ratio), its biodegradability during anaerobic digestion (AD) is usually low. In the present study, the effect of steam explosion pre-treatment on WS, combined with C/N adjustment with inorganic nitrogen, on biogas production was evaluated. Additionally, co-digestion of WS with protein-rich agri-industrial by-products (dried distillers’ grains with solubles (DDGS) and rapeseed meal (RM)) was assessed. Steam explosion enhanced biogas production from WS, whereas the addition of NH4Cl was beneficial (p < 0.05) for the digestion of steam-exploded wheat straw (SE). Furthermore, mono-digestion of the four different substrates seemed to be efficient in both inoculum to substrate ratios (I/S) tested (3.5 and 1.75 (w/w)). Finally, during co-digestion of WS and SE with DDGS and RM, an increase in the cumulative methane production was noted when hi...
Journal of Hazardous Materials
Frontiers in Microbiology, 2016
We report, for the first time, extensive biologically mediated phosphate removal from wastewater ... more We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12 • C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (∼2%) within the sludge bed and fixed-film biofilms. 4 , 6-diamidino-2-phenylindole (DAPI) staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP) granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD) removal was recorded, throughout the 732day trial, at applied organic loading rates between 0.4 and 1.5 kg COD m −3 d −1 and hydraulic retention times of 8-24 h, while phosphate removal efficiency ranged from 28 to 78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12 • C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina MiSeq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterized polyphosphate accumulating organisms (PAOs) such as Rhodocyclus, Chromatiales, Actinobacter, and Acinetobacter was recorded at low numbers. However, it is unknown as yet if these were responsible for the luxury polyP uptake observed in this system. The possibility of efficient phosphate removal and recovery from wastewater during AD would represent a major advance in the scope for widespread application of anaerobic wastewater treatment technologies.
RESUMO O metanol é um importante composto orgânico presente em diversos tipos de águas residuária... more RESUMO O metanol é um importante composto orgânico presente em diversos tipos de águas residuárias, como em indústrias de polpa e papel, amido de batata e unidade s de gaseificação de carvão. Algumas águas residuárias contendo metanol são descarregadas com altas temperaturas, tornando atrativa a aplicação do tratamento termofílico. Em ambiente anaeróbio, o metanol pode ser consumido por acetogênicas e metanogênicas. Em condições mesofílicas, a concentração do substrato, o pH do reator, a concentração de bicarbonato e a concentração de cobalto foram os fatores ambientais relevantes na conversão anaeróbia do metanol. Entretanto, pouco se conhece sobre a degradação de
Applied microbiology and biotechnology, 2014
The application of low-temperature (10 °C) anaerobic digestion (LtAD) for the treatment of comple... more The application of low-temperature (10 °C) anaerobic digestion (LtAD) for the treatment of complex dairy-based wastewater in an inverted fluidised bed (IFB) reactor was investigated. Inadequate mixing intensity provoked poor hydrolysis of the substrate (mostly protein), which resulted in low chemical oxygen demand (COD) removal efficiency throughout the trial, averaging ~69 % at the best operational period. Overgrowth of the attached biomass to the support particles (Extendospheres) induced bed stratification by provoking agglutination of the particles and supporting their washout by sedimentation, which contributed to unstable bioprocess performance at the organic loading rates (OLRs) between 0.5 and 5 kg COD m(-3) day(-1). An applied OLR above 2 kg COD m(-3) day(-1) additionally promoted acidification and strongly influenced the microbial composition and dynamics. Hydrogenotrophic methanogens appeared to be the mostly affected group by the Extendospheres particle washout as a decr...